Ernst gustav hoffmann



No. 624,492'. Patented may s, |899.'

L 6.1 nurrmxnh. DRIVE CHAIN.

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V3 is a detail to show one side of the chainof a pin or rivet of thechain-opening link.

Nrrn STATES PATENT OFFICE.

ERNST GUSTAV HOFFMANN, OF LONDON, ENGLAND.

DRIVE-CHAIN.

SPECIFICATION forming part of LettersPatent No. 624,492, dated May 9,1899.

Application led March 5 1898. Serial No. 672,755. (No model.)

To all whom t may concern.'

`Be it known that l, ERNsr GUsrAv Hort*- siding at London, England, haveinvented a certain new and useful Improvement in Drive-Chains, of whichthe following is a specification.

This invention relates to an improvement in drive-chains adapted forchain-driven cycles, as Well as for driving various machinery andapparatus, the object of the invention being to produce an easy-runningchain and one in which the stretch under wearis reduced to anexceedingly small amount by reason of the arrangement of the pins orrivets and balls forming same.

In the accompanying drawings the invention is illustrated as applied towhat is known as a roller-chain, and from this its application to ablock-chain will be easily understood.

Figure l is a sectional plan of several links of a chain. Fig. 2 is aside elevation. Fig.

opening connectingdink, its pin or rivet, and an arrangement for holdingtheballs during Withdrawal of the rivet. Fig. 4 is a similar viewshowing the opposite connecting-link and its corresponding arrangementof parts. Fig. 5 is a sectional plan showing two ends of the Workinglinks with which the above connecting-links engage. Fig. 6 is anelevation Fig. 7 is an elevation of a pin or rivet of the ordinarylinks. Fig. 8 is a plan ot' a piece of metal employed in holding theballs in the chain-opening link, and Fig. 9 is a side elevation of oneof the chain-opening connecting-links. I

The chain illustrated is made up'ot' plates d, forming theconnecting-links, and plates l), forming the Working links, the latterhaving between them at each end a roller c, though a block forming apart of the links b may be used in place of the roller, as is wellunderstood.

In Fig. 1 is shown a portion of a chain in which occurs the linkprovided for the opening of same, and such link is provided ont of oneof the connectinglinks and is formed of the plates a', as shown. Theplates a (and of course the plates CL) on each side are united by pinsor rivets cl, which pass through openings in the plates b and throughthe rollers C. The pins or rivets are providedwith a nurnber of groovese, (shown in Figs. 6 and 7,) such vgrooves having a rounded surfaceformed of the saine curvature as that of balls f, forming a series ofraces for such balls, which by reason of the curve of such grooves areprovided with a large wearing-surface on thepin.

Suitable plane surfaces are left between each groove e to separate eachseries ofballs. The plates b of the working links and the rollers c bothbear on these balls in the interior of the openings of same, suchopenings being plain curved surfaces without any races, so that theballs have a bearing only on -a small point of such surfaces.

Each end of the pins or rivets of the ordi-` nary links is reduced indiameter, as shown in Fig. 7 and when in position in the chain with theballs in place is riveted over, as shown at g at either end of Fig. l.In the case, however, of the links that require to be opened the pins orrivets are formed, as shown in Fig. 6, with one reduced end, which maybe riveted on the plate a', as shown in Fig. l, and a head g2, adaptedto pass into a keyholeshaped opening a2, Figs. 1, 2, 3, 4, and 9, of theplate a', which will be held by same when the narrow end of such openingis brought under the head g2, as it would be when t-he chain is intension. The arrangement preferred is to arrange the plates a so thatone of the slots a2 comes at the opposite end to the one on the otherside, as shown in the drawings, whereby each pin or rivet dis firmlyheld by one of the plates.

To open' the chain, the two working links connected by such plates a'are forced toward each other, so as to press the headed ends g2 of thepins or rivets into the larger end of the keyhole-slots o?, which willenable one or both of the plates a' and its attached pin or rivet to bewithdrawn. In the ordinary course the withdrawal of the pin or rivetIOC) vzo

.left between any two of the balls.

the ends of two working links from which such pins have just beenwithdrawn. The device employed for this purpose consists of a piece ofthin sheet metal h, Fig. S, provided with a number of long slots z', oneslot being for each of the series vof balls. This is bent around theballs and pin, so that the balls project for a part of their diameterthrough the slots 'L' before the pin is placed in position in the chain,and thus holding the balls to the pins whenever it is desired to removethe latter. The ends of the plate may overlap, as shown in Figs. 3 and4, at j, such ends serving to strengthen the plate. They are of such awidth that they will lie in the ordinary space The retaining device isshown in position in the chain in Figs. l and r2.

What I claim isel. In a roller-chain and in combination a pin, groovesin same, balls carried in said grooves, and a bushing forming the rollerof the chain surrounding said balls and pin, substantially as described.

2. In a drive-chain and in combination, a pin, a series of grooves insame, plates forming links in the chain "through openings in which thepin passes, a bushing forming a roller between said plates andsurrounding the pin, andv balls located in -the grooves of the pin andforming an antifriction-bearing for both the plates and roller,substantially as described.

3. In a drive-chain the combination with a grooved pin of a series ofballs in said grooves and a plate having a series of slots in same, onefor each series of balls, said plate being bent around the pin andballs, so thatthe latterproject through the slots but are held by theplate in their grooves on the pin substantially as described.

In testimony whereof I have hereunto set my hand in the presence of ltwosubscribing witnesses.

ERNST GUSTAV HOFFMANN.

Vitnesses:

ALLEN PARRY JoNEs, FRED C. HARRIS.

